Wavelength Tunable V-Cavity Laser Employing Integrated Thin-Film Heaters

A wavelength tunable V-cavity laser (VCL) employing integrated thin-film heaters is reported. The laser is fabricated by a simple process with no grating or band-gap engineering. A single-electrode-controlled wavelength tuning of 32 channels is achieved by experiment, with a tuning efficiency of 0.13 nm/mW, which is about 1.5 times higher than that of the current injection based thermal tuning. By combining four single-electrode controlled tunings with different bias currents, we obtain 51 wavelength channels covering 43 nm. Well-open eye diagrams with extinction ratios above 6.6 dB are obtained in all channels under direct modulation at 2.5 Gbps. The power penalty over a 25-km fiber transmission is less than 0.3 dB. Clearly open eye diagrams with bit error rates (BERs) below $10^{-12}$ are also obtained at 5 and 8.5 Gbps after a 10-km single-mode fiber transmission.